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Old 02-13-2018, 09:44 PM   #1
subiej257
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Member#: 464251
Join Date: Mar 2017
Default 05 sti blowing tons of white smoke

Hello, I am in need of some insight with an issue I am facing. I have done tons of research, and can't find something like what I am facing. 05 STI, 102k miles, 2.5l stock block. Car runs great, other than the clouds of smoke it plows out the tail pipe. As for mods; catted full cobb exhaust. The car wasn't tuned for the mods by the previous owner (I know, dumb), but I'm not 100% sure that's the cause of the issue. I've successfully rebuilt ej's before, but I don't wan't to dive into this one, as it doesn't seem like it's the rings.

Here's what happens;
On a cold start, smoke is quite minimal, but gets a bit worse as it starts to warm up. The smoke does smell like oil, nothing like coolant. I go for a drive (still smokes), park it, and shut off the engine. Looking at the tail pipe, its still smoking even with the engine off (but obviously not as much) - this gets me thinking turbo seal. I start it up after sitting for 10 seconds, and boom TONS of white/blue smoke comes out the back (can't see through it). Now this does seem like some sort of seal, doesn't it? I pulled the downpipe off, after the car cooled down of course, and it's black (guessing normal), but no gunk. Just the black exhaust, no signs of caked oil, no signs of cracks. Car does build boost fine, but I have been light on the throttle due to the issue. I haven't really driven the car since the smoke started happening, so maybe the turbo seal is just starting to go out? There is no shaft play at all on the turbo that I can feel (axial, or radial), and spins freely. I have cleaned out the pcv valve, and no dice. No oil in the inter cooler or cold side of the turbo that I noticed. Pulled the oil cap with the engine running, and no smoke. Oh also, if I tap the throttle, more smoke does come out as well.
I'm a bit lost here. I'm thinking worn valve seals? Maybe the turbo seal is bad? I have heard that the turbo seal can go bad, even though it has no shaft play. Also I noticed the car smoking at the header, and some oil around it, not sure what that might've been.

Anyways this got pretty long super fast haha. I could really use some help brainstorming here. Haven't really dealt with this issue, so I am a bit lost. Help would be greatly appreciated.
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Old 02-14-2018, 10:37 AM   #2
Samurai Jack
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Join Date: Jul 2002
Chapter/Region: NESIC
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2002 Enemy of Aku

Default

Quote:
Originally Posted by subiej257 View Post
Here's what happens;
On a cold start, smoke is quite minimal, but gets a bit worse as it starts to warm up. The smoke does smell like oil, nothing like coolant. I go for a drive (still smokes), park it, and shut off the engine. Looking at the tail pipe, its still smoking even with the engine off (but obviously not as much) - this gets me thinking turbo seal. I start it up after sitting for 10 seconds, and boom TONS of white/blue smoke comes out the back (can't see through it). Now this does seem like some sort of seal, doesn't it?

I'm thinking worn valve seals?
Sounds like time to start with a dry / wet compression test to check the valve seals
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Old 02-14-2018, 03:17 PM   #3
Charlie-III
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Location: USA, North NJ, 07456
Vehicle:
1998 Legacy 2.5GT
Silver Sleeper BK, 5MT

Cool

Quote:
Originally Posted by Samurai Jack View Post
Sounds like time to start with a dry / wet compression test to check the valve seals
Sorry....hate to argue.....dry vs. wet compression test will NOT test valve guides or seals.......
Neither will a leakdown test.

Sorry.......

Any of those tests WILL check piston rings, will (to a point) check valve to valve seat contact.
Valve stem seals are WAYYYYYYYY outside of any of these tests.......
Unless, the engine is ready to blow up in spectacular fashion, even then, I HIGHLY doubt it......


Again......sorry for the disagreement......

Yet again, ducking the "ban hammer"...,,,,,

PS, if you mean, "valve to valve seat" quality, then yes, I agree...... sorta what I stated, maybe just clarifying to others that "may" actually search....LOL......

A bad/poor valve to valve seat "wet test" is not particularly a good test......partly since the intake valves are up high and oil will likely not make any or much of a difference.
Just saying......
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Old 02-14-2018, 05:38 PM   #4
Vancouver98STi
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Location: Vancouver BC Canada
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1998 JDM Impreza STi
White GF8 wagon

Question

Quote:
Originally Posted by subiej257 View Post

I start it up after sitting for 10 seconds, and boom TONS of white/blue smoke comes out the back (can't see through it).
So which is it? Is the smoke white (water)... or is it blue (oil)?

Which level is dropping... oil in the crankcase, or coolant?

If it's neither, then it's just condensation burning off.
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Old 02-15-2018, 08:28 AM   #5
Samurai Jack
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Originally Posted by Charlie-III View Post
Sorry....hate to argue.....dry vs. wet compression test will NOT test valve guides or seals.......
Neither will a leakdown test.

Sorry..........
Well, maybe I didn't say what I meant? Yeah, that's it.
The way I was looking at it is:
- Compression Test - Dry
Solid compression should mean all is good
Low compression could mean bad rings/pistons/etc.
Too soon to tell

- Compression Test - Wet
If compression comes back up to where it should be, in relation to the other good cylinders, then most likely a ring/piston issue
If compression stays low, other problems exist. Start looking at valve issues, possibly in combination with ring/piston issues.
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